Real-time PCR assay for the detection of picoplankton DNA distribution in the tissues of drowned rabbits

Woo

et al. 2017

Pathological diagnosis of drowning remains a challenge for forensic science, because of a lack of pathognomonic findings. We analyzed microbiota and surfactant protein in the lungs for a novel diagnosis of drowning. All rats were divided into drowning, postmortem submersion, and control groups. The water, lungs, closed organs (kidney and liver), and cardiac blood in rats were assayed by targeting 16S ribosomal RNA of Miseq sequencing. Lung samples were analyzed by immunohistochemical staining for surfactant protein A. The closed organs and cardiac blood of drowned group have a lot of aquatic microbes, which have not been detected in postmortem submersion group. Furthermore, intra-alveolar granular staining of surfactant protein A (SP-A) was severely observed in the drowned group than the postmortem submersion and control groups. The findings suggested that the presence of aquatic microbiota in the closed organs and increased expression of SP-A could be markers for a diagnosis of drowning.

Section: Discussionsupporting

confidence: 93%

Microbiota Composition and Pulmonary Surfactant Protein Expression as Markers of Death by Drowning

Woo

et al. 2017

“…Studies have used bacteria and accumulated degree days (ADD) to measure the PMI . Other studies have confirmed drowning by detecting the genes of picoplankton living in water using molecular biological techniques . However, a specific biomarker for estimating the PMI has not been reported yet.…”

mentioning

confidence: 99%

Potential Forensic Application of Receptor for Advanced Glycation End Products (RAGE) as a Novel Biomarker for Estimating Postmortem Interval

Cho

Eom

2019

Studies which estimate the postmortem interval (PMI) based on diatoms or bacterial communities have been well‐conducted. However, predicting the PMI based on microorganisms has limited accuracy. The objective of this study was to discover specific biomarkers for estimating the PMI for drowning. The in vivo experimental model consisted of rats classified into nine groups (seven drowned groups from Day 1 to Day 7 and two control groups). Their lung tissues were analyzed for the receptor for advanced glycation end products (RAGE) mRNA expression determined by qRT‐PCR. RAGE protein levels were determined by Western blotting and immunohistochemical (IHC) staining. RAGE mRNA and protein levels gradually degraded over time. Immunostaining analysis revealed that RAGE in the Day 1 sample was significantly higher than that in the Day 6 or Day 7 samples. These results indicate that RAGE in drowned lungs could be a potential biomarker for the determination of the PMI after drowning.

“…Other methods are available to detect chlorophyll from organs using fluorescence methods (8), polymerase chain reaction (PCR)-based, and real-time PCR-based methods that detect green algae and cyanobacteria not normally present in the human body (9)(10)(11), but detection is limited to only certain types of plankton. We hypothesized that because we can detect diatoms in distal organs, then it should also be possible to detect aquatic bacteria in distal organs.…”

mentioning

confidence: 99%

Comparison between Temperature Gradient Gel Electrophoresis of Bacterial 16S rDNA and Diatom Test for Diagnosis of Drowning

Tsuboi

Takaso

Tojo

et al. 2017

When a body is discovered in water, it is difficult to conclude whether the cause of death was drowning, even today. Although diatom testing by the digestive method is classical, we hypothesized that aquatic bacteria, as well as diatoms, might be detected in drowned bodies, and conducted temperature gradient gel electrophoresis (TGGE)-targeting 16S rDNA. DNA was extracted from the site water, and from heart blood and liver samples from 27 bodies concluded as drowning deaths by autopsy and subjected to TGGE after amplification of 16S rDNA by polymerase chain reaction. We observed whether the feature point of each 16S rDNA from the site water and blood or liver samples matched. Considerably higher correspondence was observed in drowned bodies, and the rate was higher than that achieved with the digestive method. Moreover, TGGE is safer than the digestive method. Our study suggests that this method can aid diagnosis of drowning.